A comparative, multi-study analysis of plastisphere resistomes, plasmid dynamics, and antibiotic resistance genes

Microplastics are increasingly recognized as microbial habitats that can concentrate antibiotic resistance genes (ARGs) in aquatic environments.While many studies have documented the presence of ARGs within microplastic-associated biofilms, far less is known about the genomic context of these genes.This study advances the field by shifting the focus from simple ARG inventories to the plasmid architectures associated with these ARGs.By integrating metagenomic data from previously published studies spanning freshwater, estuarine, and marine systems, we provide the first comparative, cross-system assessment of the plastisphere community, plasmid replicon diversity, mobility potential, and ARG co-occurrence across different microplastic polymers.This plasmid-centric perspective reveals that ARGs in microplastic biofilms are often associated with conjugative plasmids, which can facilitate their horizontal transfer within these biofilms.Importantly, this work identifies microplastics as environments where clinically relevant ARGs are linked to plasmid architectures commonly observed in pathogenic bacteria.This work supports more mechanistic risk assessments of plastic pollution and informs One Health-oriented strategies to address antibiotic resistance across environmental, animal, and human systems.